What went wrong? : case histories of process plant disasters

cknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii Units and Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix Chapter 1.1 1.2 1.3 1.4 1.5 1.6 Chapter 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 1. Preparation for Maintenance . . . . . . . . . . . . . . . Isolation, 1 Identification, 11 Removal of hazards, 16 Procedures not followed, 24 Quality of maintenance, 32 A personal note, 44 2. Modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . Startup modifications, 48 Minor modifications, 49 Modifications made during maintenance, 55 Temporary modifications, 56 Sanctioned modifications, 58 Process modifications, 60 New tools, 63 Organizational changes, 64 Gradual changes, 66 Modification chains, 66 Modifications made to improve the environment, 69 Control of modifications, 74 48 Chapter 3. Accidents Caused by Human Error . . . . . . . . . . 78 3.1 Introduction, 78 3.2 Accidents caused by simple slips, 79 3.3 Accidents that could be prevented by better training, 90 Chapter 4. Labeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 4.1 Labeling of equipment, 98 4.2 Labeling of instruments, 101 4.3 Labeling of chemicals, 104 4.4 Labels not understood, 106 Chapter 5.1 Overfilling, 108 5.2 Overpressuring, 110 5.3 Sucking in, 114 5.4 Explosions, 117 5.5 Floating-roof tanks, 125 5.6 Miscellaneous incidents, 129 5.7 FRP tanks, 133 5. Storage Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Chapter 6. Stacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 6.1 Stack explosions, 136 6.2 Blocked stacks, 140 6.3 Heat radiation, 142 Chapter 7. Leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 7.1 Some common sources of leaks, 145 7.2 Control of leaks, 154 7.3 Leaks onto water, wet ground, or insulation, 159 7.4 Detection of leaks, 160 7.5 Fugitive emissions, 162 Chapter 8. Liquefied Flammable Gases . . . . . . . . . . . . . . . . 165 8.1 Major leaks, 166 8.2 Minor leaks, 174 8.3 Other leaks, 175 Chapter 9. Pipe and Vessel Failures . . . . . . . . . . . . . . . . . . . 179 9.1 Pipe failures, 179 9.2 Pressure vessel failures, 195 Chapter 10. Other Equipment . . . . . . . . . . . . . . . . . . . . . . . . 205 10.1 Centrifuges, 205 10.2 Pumps, 206 10.3 Air coolers, 208 10.4 Relief valves, 209 10.5 Heat exchangers, 218 10.6 Cooling towers, 221 10.7 Furnaces, 221 Chapter 11. Entry to Vessels . . . . . . . . . . . . . . . . . . . . . . . . . 229 11.1 Vessels not freed from hazardous material, 229 11.2 Hazardous materials introduced, 231 11.3 Vessels not isolated from sources of danger, 233 11.4 Unauthorized entry, 236 11.5 Entry into vessels with irrespirable atmospheres, 238 11.6 Rescue, 239 11.7 Analysis of vessel atmosphere, 241 11.8 What is a confined space?, 241 11.9 Every possible error, 242 Chapter 12. Hazards of Common Materials . . . . . . . . . . . . 244 12.1 Compressed air, 244 12.2 Water, 246 12.3 Nitrogen, 248 12.4 Heavy oils (including heat transfer oils), 255 Chapter 13. Tank Trucks and Cars . . . . . . . . . . . . . . . . . . . . 262 13.1 Overfilling, 262 13.2 Burst hoses, 263 13.3 Fires and explosions, 265 13.4 Liquefied flammable gases, 266 13.5 Compressed air, 266 13.6 Tipping up, 267 13.7 Emptying into or filling from the wrong place, 268 13.8 Contact with live power lines, 270 vii Chapter 14. Testing of Trips and Other Protective Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 14.1 Testing should be thorough, 272 14.2 All protective equipment should be tested, 275 14.3 Testing can be overdone, 279 14.4 Protective systems should not reset themselves, 279 14.5 Trips should not be disarmed without authorization, 281 14.6 Instruments should measure directly what we need to know, 284 14.7 Trips are for emergencies, not for routine use, 285 14.8 Tests may find faults, 286 14.9 Some miscellaneous incidents, 286 14.10 Some accidents at sea, 287 Chapter 15. Static Electricity . . . . . . . . . . . . . . . . . . . . . . . . 290 15.1 Static electricity from flowing liquids, 291 15.2 Static electricity from gas and water jets, 293 15.3 Static electricity from powders and plastics, 294 15.4 Static electricity from clothing, 296 Chapter 16. Materials of Construction . . . . . . . . . . . . . . . . . 299 16.1 Wrong material used, 299 16.2 Hydrogen produced by corrosion, 303 16.3 Other effects of corrosion, 305 16.4 Loss of protective coatings, 305 16.5 Some other incidents caused by corrosion, 306 16.6 Fires, 306 16.7 Choosing materials, 307 Chapter 17. Operating Methods . . . . . . . . . . . . . . . . . . . . . . 309 17.1 Trapped pressure, 309 17.2 Clearing choked lines, 311 17.3 Faulty valve positioning, 313 17.4 Responsibilities not defined, 314 17.5 Communication failures, 315 17.6 Work at open manholes, 318 17.7 One line, two duties, 318 17.8 Inadvertent isolation, 319 17.9 Incompatible storage, 319 =o= VIII 17.10 Maintenance~is it really necessary?, 320 17.11 An interlock failure, 321 17.12Emulsion breaking, 322 17.13 Chimney effects, 323 Chapter 18. Reverse Flow and Other Unforeseen Deviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327 18.1 Reverse flow from a product receiver or blowdown line back into the plant, 327 18.2 Reverse flow into service mains, 329 18.3 Reverse flow through pumps, 331 18.4 Reverse flow from reactors, 331 18.5 Reverse flow from drains, 333 18.6 Other deviations, 334 18.7 A method for foreseeing deviations, 335 18.8 Some pitfalls in hazop, 337 18.9 Hazop of batch plants, 338 18.10 Hazop of tank trucks, 340 Chapter 19. I Didn't Know That . . . . . . . . . . . . . . . . . . . . . . . 343 19.1 Ammonia can explode, 343 19.2 Hydraulic pressure tests can be hazardous, 345 19.3 Diesel engines can ignite leaks, 346 19.4 Carbon dioxide can ignite a flammable mixture, 348 19.5 Mists can explode, 348 19.6 The source of the problem lay elsewhere, 350 Chapter 20. Problems with Computer Control . . . . . . . . . . 353 20.1 Hardware and software faults, 353 20.2 Treating the computer as a black box, 354 20.3 Misjudging the way operators will respond, 359 20.4 Other problems, 360 20.5 Unauthorized interference, 362 20.6 New applications, 363 20.7 Conclusions, 365 ix Chapter 21. Inherently Safer Design . . . . . . . . . . . . . . . . . . 367 21.1 Bhopal, 368 21.2 Other examples of inherently safer design, 372 21.3 User-friendly design, 377 Chapter 22. Reactions--Planned and Unplanned . . . . . . . . 380 22.1 Lack of knowledge, 381 22.2 Poor mixing, 383 22.3 Contamination, 385 22.4 Reactions with auxiliary materials, 387 22.5 Poor training or procedures, 387 22.6 Use-by dates, 388 Appendix 1. Relative Frequencies of Incidents . . . . . . . . . . 392 Appendix 2. Final Thoughts . . . . . . . . . . . . . . . . . . . . . . . . . 395 Appendix 3. Recommended Reading . . . . . . . . . . . . . . . . . 397 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399